Expansible cartridge



Sept 29, M1942 R. c. PIERCE V2,296,947

EXPANSIBLE V CARTRIDGE Filed Feb. 5, 1940 l INVENO Y P05597' 2HE/Pcf A TTORNEYS.

@rrd @afm/9% Patented Sept. 29, 1942 eric-E EXPAN SIBLE CARTRIDGE Robert C. Pierce, Niles, .Mich., assigner to National .Standard Company, Niles, Michwa corporation of Michigan Application February 5, 1940, `Serial No. 317,349

2 Claims.

Expansible cartridges have been used in mining operations, particularly in coal mining, in place of explosive charges to blow down coal or the like from .the vein. For this purpose extremely high Vpressures are required and the cartridges are made up of `heavy rubber tubes inclosed in a reinforcing cover, one very satisfactory cover being ful'ly disclosed and claimed in my Patent No. 2,041,950.

Underthe extremely high pressures employed it vhas been found that the tube material tends to push out between the cover elements regardless of the relatively close spacing thereof. This eectis the most pronounced adjacent the ends of the cartridge where the diameter changes rapidly and where the cover elements tend to separate to a` greater .extent than at other points.

One of the primary objects of the present invention is to provide an expansible cartridge in which the tube is reinforced. According to one important feature the tube reinforcements are so arranged thatthey will not interfere with free expansion of the cartridge.

Another object of the invention relates to the provision of reinforcements which are themselves expansible so that they can expand with ff the tube.

The above and other objects, advantages and novel features of the invention will be apparent from the following description read in connection with the accompanying drawing, in which:

Figure 1 is a side View with parts in axial section of an expansible cartridge embodying the invention;

Figure 2 is a transverse section of the cartridge;

Figure 3 is an enlarged plan view of the reinforcing elements of Figures l and 2; and

Figure 4 is a view similar to Figure 2 showing another type of reinforcing element.

The illustrated cartridge comprises an expansible cover I0 shown as formed of braided tapes I2 and which may be made as disclosed and claimed in my Patent No. 2,041,950. The cover is closed at its ends by caps I4 welded or brazed to the tapes I2 and providing rigid end closures.

Within the cover I0 there is arranged an expansible tube I5 of rubber or the like and which has relatively heavy walls. The ends of the tube I6 extend into the caps I4, one end being closed fifi of the tube I6.

as shown at I8 and the other having a Aconduit 20 connected vthereto and extendingout through acap I4.

In use .the cartridge, in unexpanded condition, is placed in a hole in a vein of coal or the like and iiuid under pressure is forced `in .through the conduit 20. As the vcartridge expands to the form shown in Figure 1 it forces .out the coal or 4other material. The cover I0 serves to protect the tube from damage from contact with the coal and also prevents the tube from bursting when the coalis forceddown andits pressure against the `cartridge is relieved.

It has been found that covers lof .the `type f disclosed in my Patent No. 2,041,950 maintain a relatively close spacing between the braids I2 during all stages of lexpansion so that the tube i6 is adequately supported throughout. HOW- ever, the braids have .a tendencyto lseparate to agreater extent adjacent the caps I4 where there is a rapid change of diameter .than at other placesand .other `types of covers may separate to `a greater extent throughout.l Under .some circumstances thetube I6 .may tend to press out between the cover elements, thereby damaging the tube or the cover or both.

in order to eliminate this there are provided, according to the present invention, a series of reinforcements for the tube which hold it against pressing out between the cover elements without interfering with its free expansion. As shown, the reinforcing elements comprise elongated exible members 22 arranged in parallel in annular layers adjacent the outer portion While two such annular layers are shown in the drawing it will be apparent that more or less could be used, as desired. The members 22 preferably extend axially of the tube although they may, if desired, be given a slight twist so as to lie in a long spiral. Since the tendency for the tube to press out between the cover elements is more pronounced adjacent the ends of the cov-er than in its center portion, the reinforcing elements 22 may extend from the ends past the point of maximum curvature longitudinally and may terminate short of the center of the cartridge as shown in Figure 1.

The reinforcing elements of Figures 1 and 2 are shown in detail in Figure 3 as comprising a flat braid formed of elongated strands 24. In the form of braid shown the strands 24 cross alternately over and under two other strands back and forth across the braid although other types of braids could be used satisfactorily.

The strands 24 may be formed of brous material such as cotton, hemp, jute, wool or the like but I prefer to use metal Wires plated or coated so as to bond to the rubber of the tube I6. The braids 22 are imbedded in the tube and during curing thereof the rubber of the tube bonds to the strands 24 and to itself through the interstices of the braid so that the braid is securely anchored in place in the tube.

One important advantage of a braid of the type shown in Figure 3 is that during expansion of the tube the braid itself will expand widthwise. This enables the braids to be placed relatively close together in the layers to provide a uniform support for the tube without interfering with its free expansion.

Figure 4 illustrates an alternative form, parts therein corresponding to like parts in Figures 1 to 3 being designated by the same reference numerals plus |00. In this form the reinforcing elements are made up of substantially round cords which may be formed of fibrous material or which may be Wire cables made up with relatively ne wires. The cords, as in Figures 1 to 3, are preferably coated or treated to adhere to the rubber of the tube so that a good bond is secured.

In either case. the reinforcing elements lying adjacent the outer portion of the tube I6 reinforce and stiffen it so that it will not press out between the cover elements even though they separate to a considerable extent. Since the reinforcing elements are flexible they will readily follow the longitudinal curve of the tube adjacent its ends and will not interfere with its proper expansion.

In forming the tube the uncured rubber is molded or otherwise formed to the desired shape with the reinforcing elements in place in accordance with known manufacturing methods. The rubber is then cured to form the completed article with the reinforcing elements bonded in place and held together by the rubber.

While the invention has been described in detail in connection with two particular embodiments ii; will be understood that this description and the accompanyingv drawing are for purposes of illustration only and are not to be taken as a definition of the scope of the invention, reference being had for this purpose to the appended claims.

What is claimed is:

1. An expansible cartridge comprising a tubular braid formed of elongated metallic elements crossing over and under each other diagonally around the braid and adapted to expand radially, an inflatable tube in said braid, means for conducting uid under pressure into the tube to expand it, means closing the ends of the braid-fv whereby its expansion is limited to the portionl between the ends, and elongated reinforcing elements imbedded in the walls of the tube and lying substantially parallel to each other in layers and extending substantially axially thereof throughout the portion thereof from said end closing means to an expanded part of the tube to reinforce the tube against pressing out between said metallic elements when the tube is expanded.

2. An expansible cartridge comprising a tubular braid formed of elongated metallic elements crossing over and under each other diagonally around the braid and adapted to expand radially, an inflatable tube in said braid, means for conducting fluid under pressure into the tube to expand it, means closing the ends of the braid whereby its expansion is limited to the portion between its ends, and elongated reinforcing elements imbedded in the tube Walls and lying substantially parallel to each other in layers and extending substantially axially of the tube throughout the portion thereof from said end closing means to an expanded part of the tube to reinforce it against pressing out between the metallic elements, said reinforcing elements comprising flat braids of wires crossing over and under each other diagonally across the braid and adapted to expand widthwise when the tube is inflated.

ROBERT C'. PIERCE. 

